This invention relates generally to an apparatus for combining multiple document streams into a single merged document stream. It relates more particularly to collating multiple documents in side-by-side relation, such as those cut from a paper web, into a single merged stream of documents for further stacking or handling.
Numerous appurtenances for handling printed matter, such as mass mailing collators, are predicated on the input condition of the printed matter being fed as either a stack of documents or a single stream. See U.S. Pat. No. 5,704,604: xe2x80x9cProcess And Device For Forming And Transferring Stacks Of Printed Sheetsxe2x80x9d. Yet the greatest printing efficiencies arise when using a large roll of paper web, such as that illustrated in co-owned U.S. Pat. No. 5,505,401: xe2x80x9cMachine For Manipulating Web Materialxe2x80x9d. Printing on such industrial sized rolls of paper web typically results in three or more documents in side-by-side relation once the web is cut into individual pages.
The variety of collating systems for combining documents in side-by-side relation into a comprehensive stack or stream has been limited only to pairs of documents. See generally U.S. Pat. No. 5,947,461: xe2x80x9cApparatus And Method For Collating Documents Cut From A Continuous Webxe2x80x9d. Thus the prior art leaves a technological gap whereby the efficiencies of printing and handling of printed documents can never be simultaneously maximized.
Several attempts have been directed at closing this gap by increasing collator capacity, since collators typically have not operated at the speeds of printers. See U.S. Pat. No. 5,083,769, xe2x80x9cDual Collating Machinexe2x80x9d. In order to preclude frequent starting and stopping of the printer when the collator is running at capacity, complicated and expensive machinery has been required to provide multiple conveyor paths for documents to be merged. While effective at reducing wear on mechanical components and increasing the speed at which the printer may continuously operate, these attempts are more technically sophisticated than need be to perform the essential function of merging multiple streams of documents. They add greatly to both capital and maintenance costs, require excessive floor space, and their numerous high-speed moving parts are more prone to failure.
In typical prior art systems for handling such continuous web paper fed at widely varying speeds, the paper is provided with tractor pin feed holes along the marginal edges to track the web properly during the speed and direction changes dictated by modern printers. While attempts have been made to adapt such systems to a pinless web feeding system, such devices tend to be overly complex. See for example U.S. Pat. No. 5,820,007.
What is needed in the art is an apparatus to merge multiple document streams in side-by-side relation, such as streams printed and cut from a web, into a single merged document stream. A simpler and more compact apparatus that can be employed in both medium and large commercial printing establishments will best meet this need. It is an object of the present invention to provide this apparatus, which will alleviate some of the above deficiencies in the prior art. It is a further object of this invention to provide for merging multiple streams of documents in varying orders selected by the operator.
In accordance with the present invention, a conveyor system for merging multiple streams of documents is provided, comprising means to invert and redirect each document stream into a merged document stream, a primary conveyor to transport each document stream toward said means to invert and redirect, and a cross conveyor to transport the merged document stream away from the means to invert and redirect. In the preferred embodiment of the present invention, the means to invert and redirect further includes means to overlap at least a portion of each document in a document stream with the merged document stream.